1. Field of the Invention
The present invention relates to a spring manufacturing apparatus that continuously sends wire, which is to become a spring, to a spring forming space and performs forced bending (bending, winding, or coiling) processing on the wire using a tool, thereby manufacturing a spring.
2. Description of the Related Art
FIG. 11 is a perspective view of a tool unit, shown as conventional tool supporting means, which slidably supports a tool by a ball screw type. FIG. 10 is a plan view of a tool unit, shown as conventional tool supporting means, which slidably supports a tool by a crank type.
As shown in FIG. 11, a conventional slide tool unit 110 slides a slider 111, to which a tool is fixed, by a ball screw mechanism 113 driven by a servomotor 112.
While the tool unit 110 adopting the ball screw type has an advantage in that the amount of tool sending (sliding amount) can be linearly controlled with accuracy, it has a disadvantage in that it is vulnerable to shock received when the tool collides on object.
There is another drawback. Since the tool unit is mounted to the motor, its weight makes the handling difficult.
In comparison, the tool unit adopting the crank type shown in FIG. 10 slidably supports a slider 101 by a disc member 103 driven by a servomotor (not shown) and link members 102a, 102b, and 102c which are eccentrically attached to the disc member 103. The tool unit adopting the crank type is suitable for the processing that requires a large force (wire cutting and bending or the like) as compared with the ball screw type. Also, since a motor is not mounted to the tool unit, the tool unit has the advantage of easy handling. An example is shown in U.S. Pat. No. 6,701,765.
The above-described tool units adopting different driving methods are mounted appropriately to the spring forming table in accordance with the spring shape or the like. Since the motor mounting position differs for each tool unit, if an operator wants to change the driving method of a tool, the operator must exchange the entire tool unit and change the motor mounting position as well.
Such an operation requires not only mere exchange of the tool unit, but also fine adjustment in the mounting position of the tool unit to the forming table, and mounting positions with respect to other tool units and the motor. Such a task is extremely troublesome.